When you have just finished insulting or pissing someone off with something you say to them, this short phrase can be attached onto the end in order to tell them to "take it hard" and therefore adding more strength and power to the impact of the insult.

The gap in your teeth are so big, I don't know whether to smile back or kick a field goal! Feel it hard!

This is a phrase that can be added on to an insult, or a snap against someone's mama. It basically means to take something painfully or be hurt by it (what the person has had said to them), and increases the impact and effect of the insult by the user.